Bell peppers can be kept in the refrigerator for 3-4 days, or you can freeze them after cutting them into thin slices. To clean them, cut the caps with the stalk and remove the central part with the seeds and veins; then, rinse them under running water. You can cook them whole and stuffed in the oven, at 180° for 45 minutes, or after cutting them into thin slices, you can fry them in plenty of oil or prepare a batter. If you prefer, you can steam them for 15 minutes, grill them or simmer them in a pan over low heat.